Core catcher



J. B. RAGSDALE CORE CATCHER Filed May v19, 1931 f J3 Mcm d 2 2/ il la.:

Feb. 28, 1933.

Patented Feb. 28, 1933V UNITED STATES PATENT OFFICE JOHN B. RAGSDALE, OF WHITTIER, CALIFORNIA, ASSIGNOR. T GLOBEl OIL TOOLS COI- PANY, 0F LOS NIETOS, CALIFORNIA, A CORPORATION OF CALIFORNIA CORE CATCHER This invention relates to a device for use in a well tool, and relates more particularlyV to a core catcher for use in a core drill, or the like. It is a general object of this invention to provide a corecatcher for use in a core drill, core barrel, or the like, that is particularly effective and dependable in operation.

An object of this invention is to provide a core catcher that is simple and sturdy in construction and` that is capable of use in core drills or core barrels of various characters.

Another object of the invention is to provide a core catcher that includes a cam means or cam actuated means for gripping or biting into the core to aid in supporting the core and gripping the core so that it may be broken away from the formation at the bottom of the well bore.

It is another object of the invention to provide a core catcher of the character mentioned in which the cam means or cam-actuated means may be modified to adapt the catcher for use in obtaining cores of diderent.

types of formations.

It is another object of the invention to provide a core catcher that includes a spring means that, in some instances, may be operable to support the core and to grip the core so that it may be broken away from the formation, and a cam means that is operable to dependably grip or bite into the core so that it may be broken ofl' from the formation at the bottom of the well and that is operable to aid in supporting the core.

It is a further object of the invention to provide a core catcher of the character mentioned that is simple and positive in operation and inexpensive of manufacture.

Other objects and features of my invention will be best and more fully understood from the following detailed description of typical forms and applications of the invention. throughout which description reference will be had to the accompanying drawing, in which:

Fig. 1 is a side view of a typical core drill in operating position in a well bore and in which the core catcher provided by this invention may be embodied. Fig. 2 is an enlarged vertical detailed sectional view of a portion of the core drill, illustrating the core catcher provided by the present invention with the parts in the operating or gripping position. Fig. 3 is a vertical detailed sectional view of the lower portion of the core drill, showing a core extending into the core barrel and through the core catcher. Fig. 4 is a transverse detailed sectional view taken as indicated by line 4-4 on Fig. 2, and Fig. 5 isa vertical detailed sectional view of a portion of a coring tool or core drill, illustrating another form of the invention.

The core catcher provided by the present invention may be modified in construction to adapt it for use in various types of core drills, core barrels, etc., and for use in obtaining cores of earth formations of various characters. In Figs. 2, 3, and 4 of the drawing, I have illustrated in detail a form of the invention embodied in a more or less typical core drill and intended for use in a relativelysoft earth formation. Fig. 5 of the drawing illustrates an embodiment of the invention applied to a typical coring tool or drill, and which is intended for use in hard or rock formations. It is apparent that the core catcher may be embodied in forms for use in core drills varying considerably in ,character and in forms suitable for use in various types of earth formations, and it is to he understood that the invention is not to be construed as restricted to the particular forms or applications of the invention illustrated in the drawing.

' The coring outfit or core drill D illustrated in the drawing includes, generally, an outer barrel l0, an inner or core barrel 11, a head 12 on the lower end of the outer barrel 10, and a bit or cutting means 13 on the head.

The outer barrel is adapted to be carried and operated on the lower end of a :string of drill pipe P, or the like, and may be connected with the string of pipe by suitable connecting members 14. A sub or tubular connecting member l5 is provided on the lower end of the outer barrel 10. The end' of the barrel 10 may be screw-threaded into the upper end of the member 15. vThe head 12 is a tubular member and is attached to the lower end of the sub member 15. The member 15 is provided at its lower end with a pin 16 screw-threaded into a socket 17 in the upper end of the head.

The inner barrel or core barrel 11 is provided to receive and retain the core and is arranged within the outer barrel 10. The core barrel 11 extends downwardly -through the lower end of the outer barrel 10 and the member 15 to project into the head 12. The lower end portion of the core barrel 11 may be externally upset or enlarged and screwthreaded into the upper end of the opening 18 of the head. The core barrel 11 is mounted so that it is spaced from the interior of the outer barrel 10 and member 15 to provide an annular Huid passage F'.

The bit head or cutting means 13 includes a tubular bit body 19 attached to the lower end of the head 12. A pin 20 is provided on the lower end of the head 12 and is screwl threaded into a socket 2l in the upper end of the bit body 19. Cutting parts in the form of outwardly projecting blades 22 are provided on the bit 19. There are four equally spaced blades 22 projecting outwardly from the bit 19 and provided with suitable lower and outer cutting edges.

The core drill includes means for circulating fluid downwardly through the head 12 and bit body 19 to wash the cutting blades 22. An annular recess 23 is provided in the interior of the head 12 at the lower end of the Huid passage F. A plurality of spaced vertical openings 24 extend through the walls of the head 12 from the recess 23 to the lower end of the head. An annular recess or passage 25 is provided in the upper end of the bit body 19 to communicate with the lower ends of the openings 24. Fluid pas-Y sages 26 are provided in the bit body 19 to extend downwardly from the annular pas-- sage 25 to discharge at the forward edges of the several cutting blades 22. The present invention is not primarily concerned with the specific details of the core drill D described above, and it is to be understood that the invention is not to be-taken as limited for use in connecion with this particular type of core tool.

The form of core catcher provided by the present invention and illustrated in Figs. 2, 3, and 4 of thedrawing includes, generally, an annular body or`ring 27 mounted' for limited longitudinal movement in the core drill D, means 28 carried by the ring 27 forh engaging a core passed into the core drill for resisting movement of the ring 27 relative to the core and for gripping the core to aid in supporting it and breaking it free of the formation, and means 29 operable upon upward movement of the drill D relative to the ring 27 to tightly grip the core so that it may be broken away from the formation.

The core catcher may be arranged in any suitable posit-ion in the core receiving opening of the core drill D. In the particular case illustrated in the drawing, the core catcher is arran ed within the opening 18 of the head 12. T e ring 27 may be a simple integral member and may be proportioned to be freely movable in the opening 18. In accordance with the invention, means is provided on the coring tool or drill for limiting the longitudinal movement of the ring 27. In the particular instance illustrated in the drawing, the lower end of the core barrel 11 provides a downwardly facing shoulder 30 in the upper end portion of the head opening 18. The opening 18 is provided with an intermediate portion 31 of reduced diameter which provides an upwardly facing annular shoulder 32 on. the interior of the head. The shoulder 32 is spaced below the shoulder 30 and, in accordance with the invention, is tapered or inclined downwardly and inwardly ytoward the longitudinal center of the head.

The ring 27 is provided with a lower end portion1 33 of reduced external diameter which is adapted to extend into the opening portion 31 when 'the ring is in the down position. The ring 27 may be proportioned to have the desired amount of longitudinal movement in the opening 18. The ring 27 may be of substantially the same internal diameter as the core barrel 11 and the portion of the opening 18 occurring in the pin 20 so as to permit free passage of the core upwardly into the core barrel.

The means 28 has two functions, namely, that of engaging the core C to resist upward movement of the ring 27 relative to the core and that of gripping the core to support it or partially support it and/or to aid in holding the core so that it may be broken loose from the formation. The means 28 is in the nature of a spring means that engages the core C to resist movement of the ring 27 when the drill D is moved upwardly so as to cause actuation of the means 29, as will be hereinafter described. The means 28 includes a plurality of circumferentially spaced leaf springs 34 attached to the interior of the ring 27 The lower ends of the springs 34 may be riveted or otherwise attached to the ring 27 adjacent its lower edge. In accordance with the invention, the springs 34 extend upwardly to project above the ring 27, and their upper projecting end parts are curved or bowed inwardly to effectively engage or press against the core C. The extreme upper ends of the leaf springs 34 may be pointed and toothed, as illustrated inthe drawing, to effectively bite into the core C upon moving upwardly relative to the core. In the particular case illustrated in the drawing, secondary or inner springs 35 are provided on the inner sides of the main springs 34. The springs 35 may be attached 'to the ring 27 adjacent its lower end and may terminate adjacent the upier end of the ring. The extreme upper en parts of the inner springs 35 may be bent or bowed inwardly to engage the core. Upon the Core C passing into the lower end of the core barrel 11, the springs 34 and 35 may yieldingly engage it so that the ring 27 is moved upwardly in the opening 18 to come into contact with the shoulder 30. The springs 34 and 35 are adapted to be flexed or bent back against the walls of the core barrel 11 during passage of the core into the barrel. When the drill D is pulled upwardly to remove the core, the upper pointed ends of the springs 34 penetrate or bite into the core C and, in some instances, may be operable to grip the core in a manner so that it may be broken away from the formation and to support the core during withdrawal of the tool from the well. It will be aparent that the springs 34 and 35, in engaging the core C, operate to resist movement of the ring 27 relative to the core so that relative longitudinal movement occurs between the ring `27 and body 12 during the initial portion of the upward movement of the drill D.

The means 29 is operable upon upward movement of the drill D, or, more properly, the head 12, relative to the ring 27 to grip and hold the core C so that the core may be broken or pulled away from the formation at the bottom of the well bore and to aid in supporting the core during withdrawal of the core drill. The means 29 includes a plurality of gripping parts or dogs 36 carried by the ring 27. The dogs 36 are pivotally mounted in the interior or inner walls of the ring 27 and are operable between positions where they are substantially Hush with the inner walls of the ring and positions where they project inwardly to effectively bite into the core C. rlhere may be any suitable number of dogs 36. In the particular construction illustrated in the drawing, there is a pivoted dog 36 provided between each pair of spaced springs 34. The dogs 36 may be substantially flat rectangular members, and their'lower ends are pivotally mounted in longitudinal recesses 37 in the inner walls of the ring 27. The recesses 37 are preferably of the same configuration as the dogs 36, and are preferably suiiciently large or deep to receive the major portions of the dogs when in the up or unactuated positions. Pins 38 are provided to pivotally mount the lower ends of the dogs 36 in the recesses. The pins 38 pass through openings in the lower end parts of the dogs and have their ends welded or otherwise secured in openings 38a in the ring 27. The upper'or outer ends of the dogs 36 may be sharpened or beveled to effectively bite into the core C.

Cam means is provided for positively forcing the dogs inwardly to bite into the core C when the head 12 is moved upwardly relativo to the ring 27. The lower end portions of the recesses 36 adjacent the pivotal mountings of the dogs 36 are open to the exterior of the ring 27. The lower end portions of the dogs 36 are enlarged and are in the nature of cam parts for co-operating with the beveled shoulders 32.` When the dogs 36 are inthe up or substantially vertical positions, the enlarged cam parts on their'lower ends extend through the open portions of the recesses to project outwardly above the reduced end portion of each dog 36 to be engaged by the shoulder 32 to cause pivoting of the dogs between the vertical positions and the operating positions where they project inwardly. The cam faces 40 may be flat and may be substantially hori- -zontal when the dogs 36 are in the up or vertical positions. When the drill 12 moves upwardly relative to the ring 27, the cam shoulder 32 comes into contact with the outer edge parts of the several cam faces 40 to cause the dogs 36 to 'be swung downwardly and inwardly to bite into the core C. T hey cam faces 40 are adapted to' seat on the shoulder 32 to transmit the load supported on the dogs directly to the head 12 of the drill.

During drilling, i. e., during cutting of the core C, the core passes upwardly into the core barrel 11, as illustrated in Fig. 3 of the drawing. During passage of the core C into the core barrel, the springs 34 and 35 yieldingly engage the core so that the ring 27 is held in an up pos'tion in engagement with the shoulder 30. The dogs 36 lie outwardly in the recesses 37 when the core C is passed through the core catcher. In this manner, the springs 34 and 35 and the dogs 36 do not interfere with the free passage of the core into the drill. When suiicient core has been obtained and it is desired to withdraw the core and drill D, the drill may be moved upwardly a short dstance to ,operate the core catcher. The slight or short u ward movement of the drill D may be su cient to cause the springs 34 and 35 to bite into the core C so that further upward movement of the drill would cause the core to be broken away from the formation and be supported by the springs. However, in the event that the tool is being used in a hard or tough formation, the springs 34 and 35 may be sufficiently heavy to support the ycore, but may not be sufficiently strong to cause the core to be broken away from the formation when the drill is pulled upwardly. In the latter event, the drill D may be moved upwardly a short distance sothat the springs 34 and 35 may engage the core C to hold the ring 27 against upward movement. The upward movement of the drill D brings the tapered shoulder 32 into camming engagement with the cam faces 40 so that the dogs 36 are tilted inwardly a suiicient amount to obtain a grfp on the core. Upon the dogs 36 obtaining a grip on the core C, further upward movement of the drill causes the dogs to bite or penetrate more deeply into the core so that it may be readily broken away from the formation. After the core has been loosened from the formation, the drill D, carrying the core, may be withdrawn from the well. The dogs 36, as well as the springs 34 and 35, operate to effectively support the core in the core barrel. It is to be noted that the biting thrusts and supporting strains to which the dogs 36 are subjected are directly transmitted to the head 12 of the drill through the engagement of the cam faces 40 with the shoulder 32. This construction permits the use of comparatively light pivotal pins 38 so that the core catcher may be embodied in a compact form. It will be apparent that the core catcher illustrated in Figs. 2, 3, and 4 of the drawing is particularly effective as it is dependable in its operation and is simple to actuate. The dogs 36 provide a positive means for gripping and biting into the core C so that the core may be effectively broken away from the formation.

The form of the invention disclosed in detail in Figs. 2, 3, and 4 of the drawing is intended primarily for obtaining coresl of relatively soft formation. The embodiment of the invention disclosed in Fig. 5 of the drawing is intended for use in obtaining cores of hard or rock formation. The core catcher illustrated in Fig. 5 of the -drawing ma be used in connection with a core drillD o the character described above; however, it is to be understood that it is not limited for use in this particular type of tool. The core catcher illustrated in Fig. 5 of the drawing includes, generally, a ring 27 movably mounted in the head 12 of the drill D, spring means 28a for engaging the core, and cam means 29a carried by the ring 27 a for gripping the core.

The ring 27a may be similar tothe ring 27 described above and may be mounted in the head 12 in the same manner, i. e., it may be movable between the shoulder 30 and the beveled shoulder 32. The ring 27a fits the head opening 18 with suitable clearance. The spring means 28a may be identical with the means 28 described above, i. e., it may include a plurality of main upwardly projecting springs 34a and shorter springs 35a. When the core catcher is to be employed in hard or rock formation, the springs 34a and 35a are primarily intended to frictionally engage the core to provide for the desired relative movement between the ring 27a and the body 12 when the drill is operated to break away the core.

The means 29"L is carried by the ring 27a and is provided to positively grip and hold the core. The means 29a includes a plurality of gripping members or dogs 6() carried by the ring 27a. The dogs 60 are in the nature of pivoted gripping cams and are carried in circumferentially spaced slots or openings 61 in the ring 27a. The lower ends of the cam dogs 6() are pivotally mounted in the lower end parts of the openings 61 by pivot pins 62. The inner sides or eXteriors of the gripping members are in the nature 0f segmental or arcuate faces eccentrically. curved about the pivotal axes of the dogs. The inner eccentric faces of the dogs may be roughened or suitably toothed to effectively grip the core. Cam faces 63 are provided on the lower ends of the dogs to co-operate with the beveled shoulder 32 to cause inward pivoting of the dogs when the drill is raised to remove or break off. the core. The cam dogs 60 are proportioned so as to normally lie within the openings 61 when the ring 27 a is in the up position during passage of the core into the drill.

The operation of the form of core catcher illustrated in Fig. 5 of the drawing is similar to the operation of the type of device illustrated in Figs. 2, 3, and 4 of the drawin During they passage of the core upward?)7 into the core barrel 11, the springs 34a and 35a frictionally engage the core so that the ring 27at ismaintained in an up position against the shoulder 30. When the ring 27a is in this position, the cam dogs 60 are in the up or out positions within the openings 61` where they do not interfere with the free passage of core into the core barrel. When it is desired. to remove or break olf the core, the drill may be moved upwardly. Upon upward movement of the core drill, the spring iingers 34?' and 35a engage the core to hold the ring 27a against upward movement. Upward movement of the drill brings the shoulder 32 into engagement with the cam faces 63 of the dogs and causes the dogs to be pivoted -inwardly so that their eccentric gripping faces engage the core. Upon the dogs obtaining a grip on the core, further upward movement of the drill causes the dogs to more tightly grip the core. When the dogs have been fully actuated, i. e., when they have obtained their full supporting grip on the core, the cam faces 63 are in supporting enagement with ythe shoulder 32 so that the oad or weight supported by the dogs is directly transmitted to the body 12. It is to be noted that the embodiment of invention disclosed in Fig. 5 of the drawing is particularly adapted for use in hard or rock forniation as the gripping dogs 60 are operable to effectively and tightly grip hard cores. It will be apparent that the eccentricity of the gripping faces or dogs and the extent to which the dogs may project into the corepassing opening may be varied to adapt the core catcher for use in obtaining cores of various characters. ensure the correct operation 0f the gripping dogs 60 as it provides for the necessary relative longitudinal movement between the body l2 and ring 27 a when the drill is moved ur:- wardly.

The spring means 23a Having described only typical preferred forms of my invention, I do not Wish to limit myself to the specific details set forth, butl wish to reserve to myself any changes or variations that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. A core catcher for use in a tubular tool including, a ring mounted in the tool for longitudinal movement relative thereto, means on the ring for contacting with a core extending into the tool to resist upward movement of the ring relative to the core, a dog pivotally mounted in the ring and operable to grip the core, there being an opening in the ring adapted to receive the entire dog so that it does not project into the central opening of the ring during passage of the core int/o the tool, and a cam part on the tool to actuate the dog into the central opening of the ring upon upward movement of the tool relative to the ring.

2. In a core drilling tool, a tubularbody having a flat downwardly and inwardly inclined shoulder, a core barrel stationarily mounted in the body, a core catcher in the body including a ring movable longitudinally in the body between the lower end of the core barrel and the shoulder, means carried by the ring to resist movement of the ring relative to a core extendin into `the body and operable to aid in carrying a core, a pivoted dog carried by the ring for gripping the core, and a fiat cam part on the dog for engaging the shoulder to actuate the dog upon relative movement between the body and ring and adapted to flatly seat on the shoulder when the dog is fully actuated.

3. In a core drilling tool," a tubular body having a shoulder, a core catcher in the body including a ring movable longitudinally in the body, spring fingers on the ring for engaging a core extending into the body to resist movement of the rlng relative to the tive to the core, a plurality of openings in the ring spaced between the spring fingers, a plurality of dogs pivotally mounted in the openings and operable between positions completely housed in the openings where they are free of the core to positions where they grip the core, and cam parte on the dogs adapted to be engaged by the shoulder to move the dogs to the gripping positions upon upward movement of the body relative to the ring and adapted to transmit the gripping and carrying thrusts from the dogs to the shoulder.

5. A. core drilling tool including a tubular body having an internal shoulder, a core barrel stationarily mounted in the body and having its lower end spaced above said shoulder, and a core catcher inthe body including a ring in the body movable longitudinally between said shoulder and the lower end of the core barrel, the ring being freely rotatable relative to the body and core barrel, spring means on the ring for engaging a core extending into the lower end of the body to resist movement of the ring relative to the core, the ring having spaced openings, and pivoted dogs in the said openings, the dogs having cam parts operable through engagement with the shoulder upon longitudinal movement of the body relative to the ring to operate the dogs into gripping engagement with the core.

In witness that I claim the `foregoing I have hereunto subscribed my name t is 13th day of May, 1931.

. JOHN B. RAGSDALE.

core, there being .a pylurality of spaced'openings in the ring, a plurality of dogs pivotally mounted in the said openin and operable between positions complete y within said openings where they are free of the core to positions where they project into the central openings of the ring to grip the core, and cam parts on the dogs for engaging the shoulder to move the dogs to the gripping positions upon movement of the body relative to the ring.

4. In a core drilling tool, a tubular body having a shoulder, a core barrel stationarily i mounted in the body, a core catcher in thebody including a ring movable longitudinally in the body between the shoulder and the lower end of the core barrel, a plurality of circumferentially spaced spring fingers in the ring for engaging a core extending into the body to resist movement of the ring rela- 

